This invention relates to a blind rivet of a construction such that the blind rivet can be used for fastening itself to a fitting hole perforated in a given part or, in the case of a part composed of a plurality of members, for binding the plurality of members mutually to one another into a unitary part by a simple operation of lifting the shank thereof upwardly relative to the rivet body on one side of the part and that once the desired fastening is completed, the blind rivet seals the opposite openings of the fitting hole in the part with a high degree of water-tightness.
The conventional blind rivets also include those of a simple basic construction wherein the shank is made of a metallic material and provided at the leading end thereof with an expanded portion and the rivet body is made of a synthetic resin and disposed round the shank, so that desired fastening of the rivet to a given part is accomplished by lifting the shank upwardly relative to the rivet body and consequently causing the rivet body to be expanded outwardly in the radial direction and pressed against the part. After the shank has been lifted up, the head portion of the rivet body must be caulked to fasten the shank in its lifted position to the rivet body. Thus, the blind rivet is not bound with ample stability to the part and the binding force exerted by the rivet on the part is often insufficient.
Other blind rivets developed to date have a basic construction similar to the construction described above, except for a modification wherein the rivet body is separated into an upper portion and a lower portion provided respectively with male screw means and female screw means as shown in U.S. Pat. No. 3,521,521. In this case desired fastening of the blind rivet to a given panel part is accomplished by rotating the shank and consequently allowing the two portions of the rivet body to be brought into engagement with the lower portion overlapping the upper portion, so that the rivet body as a whole is expanded outwardly in the radial direction and pressed tightly against the panel part.
In the blind rivet of this construction, however, the operation of rotating the shank is troublesome and the operability of the blind rivet is notably inferior. Moreover, the strength of the radially expanded rivet body is inferior because of the formation of screw threads thereon.
For the purpose of remedying the various shortcomings suffered by the conventional blind rivets, the inventors of the present invention have proposed blind rivets of a basic construction wherein the rivet body is bent outwardly in the radial direction and finally folded over itself by the upward lift of the shank and, consequently, the rivet body is expanded radially.
These blind rivets of the present inventors are excellent in the ginding force they exert upon the given panel parts, provide ample water-tightness for the openings in the panel parts and enjoy high practical utility. Thus, they have found favorable acceptance in the market.
An object of the present invention is to make further improvements in the blind rivets proposed to date by the inventors and provide a blind rivet of plastic material which has a high binding force and water-tightness, excels in operability and riveting effect and has good tolerance to variation in the thickness of panel parts.